Silver Ion Inhibits Ethylene Synthesis and Action in Ripening Fruits1

Abstract

Abstract Ag(I), applied in aqueous solution as AgNO 3 , inhibited ethylene synthesis and ripening of mature green banana fruit slices and pericarp discs of mature green tomato fruit. It also inhibited ethylene production by cortical tissue from post-climacteric apples. Concentrations of Ag(I) which reduced ethylene synthesis had an inconsistent effect on CO 2 production: no effect on banana slices (1.0 m m Ag + ), stimulation in apple tissue (0.1 m m Ag + ), and inhibition in tomato tissue (0.3 m m Ag + ). This was accompanied by a slight amount of tissue necrosis at these concentrations. Of the 7 metallic salts tested, only Ag(I) inhibited ripening and ethylene synthesis at observed non-phytotoxic levels. Inhibition of ripening and ethylene synthesis by Ag(I) was evident in tissue treated with sufficient exogenous ethylene to elicit both responses in control tissue. The inability of applied ethylene to overcome the inhibitory effect of Ag(I) suggests that the silver ion may interfere with the primary action of ethylene in the tissue.